Business communications company Daisy Group has completed a £1m upgrade to its Manchester data centre and has unveiled plans to open a fifth UK site by the end of the year.

Daisy has carried out a raft of improvements to boost capacity and efficiency at the underground Manchester complex, which sits behind a 12-tonne bomb-proof door in a former Bank of England vault in the city centre.

The investment increases capacity by 50 per cent, taking the number of servers from 2,000 to 3,000.

Daisy has installed additional power and cooling infrastructure so that another 1,000 servers can be installed in the future, which would give it sufficient capacity to accommodate at least two years' growth.

Director Will Kennedy said: “We are investing very heavily in enhancing our network to enable us to deliver cloud computing to our clients and store their data effectively.

“As more and more businesses go online, there is increased demand for secure services, which require more power.

“That generates a lot of heat, so we have also had to invest in our cooling systems.”

Mr Kennedy said Daisy was currently looking at another data centre site in the south of the country which would see a seven-figure investment and is planned to come online by early 2013.

Nelson-based Daisy currently has data centres in London, Southampton and Jersey.

The Manchester data centre, which is 25ft below ground, has granite walls which are two metres thick.

It is continuously monitored by 70 CCTV cameras and houses critical data for companies including Manchester Airports Group, Racing Post and Trinity Mirror, publisher of the Manchester Evening News.

It has three stand-by diesel generators, to be triggered in the event of a power failure, and a cooling system equivalent to 2,000 domestic fridges.

But increased energy efficiency means the new improved centre will use £25,000 less electricity a year.